My post actually was a bit out of sequence as indicated by the quote. I have not been following this thread closely. The point about the Columbia reentry reflected my pet peeve about press coverage following the Columbia failure. For wings sharp enough to fly decently (and the shuttle is a compromise with a poor glide angle) temperatures can approach those on the Sun.

Variable geometry systems (and even wings which fold on the ground) have a poor reliability and high maintenance history in both military and homebuilt designs. I know of no commercial examples, since they have no reason to accept these extra costs. That doesn’t mean they are impossible.

To date the SpaceShipOne has had only one in-flight “anomaly” related to its folding design, and that was with the necessarily unlinked tail surface activators in the design. This had the acknowledged potential to destroy both the spacecraft and its pilot. Disaster was averted by spontaneous recovery of the activating system, something I usually call a miracle. This happened on one of three spaceflights.

I would not brag about the exceptional safety of a system which had this operational history!

Yes, it is an interesting design, which exchanges widened reentry attitude tolerance for more complex aerodynamic mechanisms (compared to the X-15). Yes, it has been made to work. Yes, it can probably be engineered to a configuration which has the redundancy and failsafe attributes to be operationally used. And it may even be one of the few suborbital designs which are both forgiving at reentry, and can be conventionally landed on a runway.

Can you think of a nice blunt shape, with the wings and tail folded into the protected subsonic airflow? I can, and have, but I don’t think I could get it to work adequately and am not going to build one! But this is probably what a safe runway landing spacecraft will look like.

This thread suggests that the Falcon V is believed to be marginal for the 5 man ASP goal. Accepting that idea, any air launch system would have to get the Falcon V to release altitude. A fifty thousand foot air launch (if possible), can reduce the air drag loss for a large launch vehicle by no more than 5% of required, orbital delta V (it can be up to 30% of the much smaller, suborbital delta V). The 5% advantage could reduce the launch weight by 20%. If the carry/drop/and launch hardware was only 25% of the flight weight, then the equivalent of the original weight would need to be carried to altitude. This still sounds like a custom designed Airbus A380 to me! Shave some cost for pilot production only, with thorough testing, but WITHOUT certification. What’s your cost estimate? (And remember that vendors and governments are not going to be sharing the development costs and risk!) I don’t think anyone is going to build this air-launch system.

5400 kilos to the ISS is way more than five noses. Even if you factor in some ridiculously heavy re-entry vehicle (niconel or whatever) you still have lots of capacity remaining.

Now, the SpaceX site is less than technically informative, but you can download the Payload User Guide in pdf format for Falcon 1 (it's not out yet for V).

It (the userguide) also doesn't give you all the info you need, but it is possible to interpolate the data therein to learn that Falcon 1 burns approximately 20% of its propellant (stellar guess, rp!) to reach the ~30,000 ft. (not 50 K) altitude that t/Space is talking about making their drop from. Musk's bird is also not yet transonic, so the mission profile of Falcon 1 is at that point comparable to QuickReach(whatever) immediately prior to the release. Except that the VLA doesn't have to haul that 20,000 gallons of propellant. Falcon V uses the exact same engines, just more of 'em, I expect that payload scales, fuel loads, and trajectory plots will be similar. Assuming we think that a 5-man capsule will have 5400 kg of mass. Which we don't, right? VLA would be on a similar scale to A380 (why do you think they are also talking about a 747?), but not impossibly large.

OK, I can hear all of you now, "But look at how much money you have to spend to build VLA!! (or retrofit the jumbo) Musk just has to pay for LOX and kerosene!"

Musk just has to pay for kerosene, and for shipping his bird to the Marshalls 'cuz Vandy says he can't play in thier sandbox until October. Good thing his client bears some connection to the delay, or he'd have some 'splainin to do. Flexibilty of launch scheduling and basing is a consideration whose economic value has yet to be determined. If someone wants to fork over some cash to find out how marketable that commodity is, I say more power to 'em.

Besides, I'd be just giddy if we didn't have all of our human-rated orbital spacecraft eggs in one freakin' basket!

I missed the fact that you were talking seriously about retrofitting a 747. That would be a whole lot cheaper than developing a custom airframe. (Perhaps $100 Million for an old bird, versus over $10 Billion for a new design?) I have to admit that I have trouble thinking in that price range, but I agree that it could be done. Actually I like the C5A better, with the open tail and drag and drop release mode. Possibly you could modify the 747 to work this way.

I agree completely that the launch site problem is HUGE, and may justify the cost. Personally, I am counting on offshore, marine launch. And yes, I know that Boeing spent over One Billion $$ on their (refurbished) “Sea Launch” platform. But I think that a marine system for “Ultralight” launches will cost a lot less (and be more schedule friendly) than the “traditional” launch sites.

Yes, I personally think that the Falcon V will handle a lot more than five tourists. I think the Falcon I should be able to handle three. But earlier posts expressed doubt about even the Falcon V for ASP. In any case we are talking about a BIG launch aircraft, something far larger than the White Knight. Realistically, this aircraft should be twenty times the gross weight! The many references to SpaceShipOne, as if it were in any way comparable to what the ASP will take, keeps me confused.

By carefully screening out the noise on this topic, I can see that some of you do have a fair idea of what it will take. Personally, however, I don’t have the faith to believe that kind of money will become available, so I will stick to “thinking small”.

Wouldn't the A380 be somewhat better suited to this than the 747, considering its sheer size? And remember, rpspeck, any aircraft that you use (C-5 or no) will have to be extensively modified: not even a Galaxy can have a rocket slide out its back end without some serious issues (remember how the C-130 jumped after releasing the MOAB?).

The biggest problem I have with a marine launch system is the fact that I live in Florida, watched through the 2004 hurricanes, and have a vague idea of what a Cat 5 (or even a measly 2 or 3) storm could do to a marine launch complex. Trust me, it ain't purty.

The greatest advantage of an air-launch system is its ability to operate completely independent of the weather, by simply flying around the bad spots. So if flexibility is any sort of an issue, then an air-launch system is a pretty sure bet. If I was FedEx or the military, this is definitely the launch system I'd be interested in.

Of course. But that doesn't mean that, when the weatherman says "Thar's a storm a-brewin'", the airplane can't take off early and avoid the storm completely by flying to another location.

You're obviously not loading passengers onto something like that then. When has an airline ever phoned you up to say that you have to get to the airport an hour earlier because theres a front a-coming in?

Besides, what sort of ground launch system are you comparing your air-launch system to? Armadillo? Why couldn't Armadillo take off early as well?

I'm still not buying the weather advantage of air-launch. There are other advantages, but that aint one of them.

You're obviously not loading passengers onto something like that then. When has an airline ever phoned you up to say that you have to get to the airport an hour earlier because theres a front a-coming in?

Hrmph. Point taken; that would only work for cargo launch, and only if the payload was already on-site. It should be possible, however, for an air-launch system to avoid high-level conditions by flying underneath them to a location that was not effected. This way, while a ground-launch rocket is effected by all weather conditions, an air-launch system might only be effected by low-level problems. I stress might.

To buy direct from Boeing is going to cost a pretty penny--and it still isn't going to move that wing up any. You might be better off buying two old B-52s--use the two fueslages as Rutan-Booms--and put the t/Space rocket between the two fuselages.

That is cheaper than the twin C-5A contraption, isn't it? Maybe get a law passed where the boneyard has to give t/Space two of them under orders from the military.

I still think the AN-225 is best, though.

The B-52 is a strange bird. It is both the most--and least--conventional airplane we have. It doesn't rise its nose off the ground--the whole thing lifts straight up and crabs into the air. The strange landing gear allows for the thing to very well land sideways due to the bogies.

A twin fuselage B-52 VLA would be the most "Rutan-like" answer--the flexible wings and double boom construction and all.

The attachment span between both B-52s could rise in the middle--so that the t/Space rocket would be recessed in an A-frame notch, if you will.

Just a thought.

This is costly but gets you a shoulder-mounted wing: (from starshipmodeler)

as I think about it one weather-related advantage of air launch seems to be left: The vertaical ground launcher is forced to go throught the bad weather - but the airplane which carries the vehicle to be air-launched can leave the bad weather-region and delay the air launch until a region with reasonable weather is reached.

So the vertical ground-launcher is forced to pass dangerous clouds and winds while the air launched vehicle is not.

It is not required that the airplane lifts earlier if the option of a delayed release and ignition of the carried vehicle is choosed. A region will be known where the weather is reasonable and so the delay can be calculated which is not the case regarding the duration of the bad weather at the launch site of the vertical ground-launcher.

Regarding suborbital flight it will be interesting if during the XPRIZE CUP such a situation will occur and if in that case the concept of air-launching will decide the race.

It is still best to have a base for the aircraft close to the coast--Mobile say.

On the B-52 as carrier--you would have two remove the port wing on one--the starborad wing on the other--salvage the engines, etc. At least it is low to the ground--where you could roll the t/Space booster between the fuselages on pallets.--but it would be a gimpy take off.

AN-225 is less a hassle. Bring that second one here (use 777 engines in-board), and put a glass cockpit in it. It has room for six people in the cockpit. Their workstations would be replaced with the screens/readouts for the actual t/Space rocket--a control room behind the cockpit if you will.